Field of the Invention
The disclosed technology relates to probe assemblies adapted for probe-based characterization techniques, such as surface analysis techniques including scanning probe microscopy techniques such as atomic force microscopy (AFM) and related techniques, or nanoprobing techniques. More particularly, the disclosed technology relates to probe configurations that are formed at least partly of diamond-based materials, and methods of manufacturing such probe configurations.
Description of the Related Technology
Scanning proximity microscopy or scanning probe microscopy (SPM) systems, such as an atomic force microscopy (AFM) system, a scanning tunneling microscopy (STM) system, a magnetic force microscopy (MFM) system, a spreading resistance microscopy (SSRM) system, operate by scanning the surface of a sample with a probe having a small tip. The probe configuration typically comprises a mounting or holding block to which a cantilever, also known as stylus, is mounted. Attached to this cantilever is a tip which is pointing towards the sample surface when scanning this surface. This tip preferably has a high hardness and low wear. The tip and the holding block are mounted at opposite ends along the length of the cantilever. During the scanning of the surface, the sample is moving relative to the tip either by movement of the sample only, by movement of the tip or by a combined movement of both tip and sample.
Such a probe can be used for measuring the topography of the sample's surface by sliding the probe over the surface and monitoring the position of the tip at each point along the scan line. In this application the conductive properties of the tip are less relevant and dielectric or semiconductor materials can be used to manufacture the tip. The probe can also be used for determining the electrical properties of a sample, for example the resistance and electrical carrier profile of a semiconductor sample. For these applications at least the tip of the probe must be conductive.
Another application which makes use of a probe configuration is nanoprobing. A nanoprobing system typically comprises a scanning electron microscopy (SEM) system for viewing the surface of the sample to be probed or scanned, nanomanipulators (also often referred to as nanoprober) comprising the probe configuration for contacting the surface and parameter analyzer(s) for performing electrical measurements of the sample via the nanomanipulators. So far, only manually etched tungsten probes are available as probe tips for the nanoprobing system. The tip sharpness is limited to about 20-100 nm. Such tungsten probes are easily damaged while repeatedly contacting the sample surface and they show rapid wear and have a low lifetime. They are not hard enough for probing semiconductor materials such as Si and Ge.
For SPM applications there is a strong need for highly conductive, sharp and strong tips which may overcome the disadvantages of prior art tips.
For nanoprobing applications, there is a strong need for microfabricated tips instead of manually fabricated tips. Moreover alternative materials besides tungsten should be usable as tungsten tips suffer from oxidation and are not hard enough for probing on Si and Ge. The tips should also be sharper to improve the attainable resolution in the nanoprobing measurements.
There is thus a need for a probe configuration which allows for characterizing a sample with (ultra) high resolution with high yield, which can be manufactured cost-efficiently and where the tip has a high hardness, high conductivity and thus a high dynamic range detectability.